Immusol, Inc., has created two ribozymes, CR2 and CR4, that efficiently cleave hepatitis C virus (HCV) RNA is hepatocyte culture. In order to achieve high level stable expression of these ribozymes for HCV gene therapy, Immusol will develop a novel chimeric adenovirus-based vector system that incorporates adeno-associated virus (AAV) inverted terminal repeats (ITR). The chimeric vector will be able to grow to high titer and will be efficient at transducing hepatocyte cells. The presence of AAV ITRs will mediate the integration and stable expression of the transgene(s) in the transduced cells. To increase the efficiency of transgene integration, established techniques will be used to conjugate an AAV replication gene-expressing plasmid to the chimeric virus particles by polylysine. In addition, chimeric vectors will be tested which transiently express rep protein. The effectiveness of CR2 and CR4 ribozymes in chimeric vectors against HCV RNA will be tested in a hepatocyte culture system. After a successful phase I in vitro study, the applicant proposes to initiate an SBIR phase II animal study for the effectiveness of the ribozymes in inhibiting HCV replication and a phase I clinical trial with HCV-infected patients using ribozymes delivered by an adenovirus-AAV chimeric vector. PROPOSED COMMERCIAL APPLICATION: Potential commercial application not available.